1. Technical Field
The present invention relates to a recording device for printing a desired image on a recording medium of which a printing surface has shapes except for a rectangular shape, that is, different shapes, and more particularly, to a recording device that prints a desired image on a label surface of a circular optical disk used as a recording medium.
2. Related Art
In recent years, an original music album, a photographic album, a DVD album, and the like could be easily made by using an optical disk drive (hereinafter, referred to as an ODD) corresponding to an optical disk (hereinafter, referred to as an optical disk) used as a recording medium, such as a CD-R (Compact Disk Recordable), a DVD-R (Digital Versatile Disk Recordable), a CD-RW (Compact Disk ReWritable), or a DVD-RW (Digital Versatile Disk ReWritable). For this reason, there is a demand for the printing of a label of the made optical disk with an original design.
Accordingly, in the past, there has been proposed a recording device that can print an image of a desired label on a printable area of a printing surface of an optical disk (see, e.g., Japanese Unexamined Patent Application Publication No. 2007-188590, inkjet line printer).
If the recording device is a thermal transfer recording device using a thermal head where a plurality of heating elements are linearly arranged, regardless of whether an ink ribbon is used, an optical disk is transported to the downstream side from the upstream side in a transport direction, a pressing load is applied to the thermal head so that the thermal head comes in contact with the optical disk, and current is selectively applied to the heating elements.
In this case, a pressing load, which is applied to the thermal head, has been made constant by using the elasticity of a spring. For this reason, if recording is performed on a circular optical disk having a predetermined thickness, the linear contact length of the printing surface of the optical disk coming in contact with the thermal head is short when the thermal head comes in contact with a circumferential portion of the optical disk, that is, front and rear end portions of the optical disk in a transport direction (directly before recording begins to be performed or is terminated). Accordingly, extreme pressure or high contact pressure (linear pressure) is applied to the contact portion. In contrast, when the thermal head comes in contact with a portion of the optical disk that is close to the diameter of the optical disk (while recording is being performed), the linear contact length is longest. Therefore, contact pressure is lowered. Specifically, there has been known that contact pressure is changed tenfold or more between when the recording begins to be performed and when recording is being performed. The change in contact pressure during a series of recording causes a disadvantage, such as color unevenness generated on a recording result.